This invention broadly relates to a wafer carrying system, and in particular, to a wafer carrying system including an intermediate cassette device having a plurality of wafer support holders, a robot arm device for carrying a wafer, an aligner unit for aligning the wafer, and a wafer feed and storage cassette, and to a carrying method thereof.
Shown in FIG. 5B is a cross-sectional view of the wafer holding and rotating part 31. The wafer holding and rotating part 31 includes a vacuum chuck. The vacuum chuck has an opening 31-3 located at the top surface of 31. The opening 31-3 continues to a pathway for vacuum line 31-2. Vacuum drains 31-4 are compartments of suction opening 31-3. The wafer holding and rotating part 31 is holds wafer 22 by vacuum power.
Conventionally, as shown in FIG. 1, a wafer 101 is carried once from a wafer cassette 104 to an aligner unit 102 by a robot arm 105, and then, the aligned wafer 101 is carried to an intermediate cassette (shuttle) 103.
More specifically, the wafer 101 is aligned by the aligner unit 102 separately located from the intermediate cassette 103 to appropriately set the rotational position of the wafer 101 using a mark such as an orientation flat (a notch), and then, the wafer 101 is loaded on the intermediate cassette 103. Herein, it is to be noted that numeral 105 denotes a main cassette (a vacuum cassette) while numeral 106 denotes an unloading cassette (a shuttle).
For example, when the wafer 101 is carried from the wafer cassette 104 to the intermediate cassette 103, the carrying path is: the wafer cassette 104xe2x86x92(carriage by the robot arm 105)xe2x86x92the aligner unit 102xe2x86x92(carriage by the robot arm 105)xe2x86x92the intermediate cassette 103; and thus two carriages by the robot are necessary.
It is therefore an object of this invention to provide a wafer carrying system which is capable of carrying each wafer in single operation of a robot device, and which is capable of shortening the changing time of a treated wafer with an untreated wafer, and a carrying method thereof.
According to an aspect of the present invention, a wafer carrying system comprises an intermediate cassette device having a plurality of wafer support holders, a robot arm device to carry the wafer, an aligner unit mounted below and extendable into the intermediate cassette device to align the wafer, and a wafer feed and storage cassette.
With such a structure, the wafer held by the robot arm device is transferred to the aligner unit, and aligned in the intermediate cassette device, and then, directly delivered from the aligner unit to a plurality of wafer support holders of the intermediate cassette device.
The aligner unit has a positioner, and the wafer is centered by the positioner and transferred to a wafer holding and rotating part by the vertical movement of the wafer holding and rotating part of the aligner unit or the positioner.
Further, the wafer is centered by the positioner on the aligner unit in which the positioner is provided in a concentric manner, is transferred to the wafer holding and rotating part of the aligner unit, and is delivered to a next process by the vertical movement of the whole aligner unit.
The center of the aligner unit and the wafer loading center of the intermediate cassette device are disposed concentrically with each other.
The aligner unit is horizontally moved to the intermediate cassette device to transfer the wafer so that the center of the aligner unit and the wafer loading center of the intermediate cassette device are disposed concentrically with each other.
The intermediate cassette device is horizontally moved to the aligner unit so that the center of the aligner unit and the wafer loading center of the intermediate cassette device are disposed concentrically with each other.
The center of the positioner of the aligner unit and the center of the wafer holding and rotating part of the aligner are disposed concentrically with each other in the vertical direction.
The aligner unit can be vertically raised/lowered, and wafers are successively loaded from the aligner unit to an upper end of the stage to a lower end of the stage of a plurality of wafer support holders of the intermediate cassette device by the raising/lowering operation of the aligner unit.
The aligner unit is disposed on the wafer-loading-center locus on a wafer insertion path of the intermediate cassette device, and the aligner unit is horizontally moved to receive the wafer from the robot arm device.
The aligner unit is horizontally moved and receives the wafer from the robot arm device, and the intermediate cassette device is vertically moved to transfer the wafer.
The plurality of wafer support holders of the intermediate cassette device have an open-bottom cavity space part, and the aligner unit can be vertically raised/lowered within this among the cavity space part.
The positioner and the wafer holding and rotating part of the aligner unit can be vertically raised/lowered among the open-bottom cavity space part of the plurality of wafer support holders of the intermediate cassette device.
The intermediate cassette device can be vertically raised/lowered, and the wafers are successively transferred from said aligner unit to the plurality of wafer support holders of the intermediate cassette device, and moved from an upper stage to a lower stage of the intermediate cassette device by the raising/lowering operation of the intermediate cassette device.
The aligner unit is disposed on the horizontal moving line of the intermediate cassette device or on a wafer-loading-center locus during the rotation by the shuttle drive, the wafer is delivered by horizontally moving the intermediate cassette device, toward the aligner unit and the aligner unit is vertically moved.
The intermediate cassette device is horizontally moved to deliver the wafer, and the intermediate cassette device is vertically moved.
The wafer is delivered from the robot arm device to the aligner unit, the vertical position of which can be changed by up/down movement, and the aligner unit or the intermediate cassette is vertically moved to receive and transfer the wafer.
The robot arm device is vertically moved during the carriage of the wafer from the feed and storage cassette, and the wafer is delivered to the aligner unit, the position of which can be changed by vertical movement, and the aligner unit or the intermediate cassette is vertically moved to receive and load the wafer.
The wafers are loaded in the empty wafer holding shelves of the intermediate cassette device, the intermediate cassette device is unloaded, then the same reloading process occurs.
A sensor to detect an orientation flat (or notch) of the wafer is installed in an inclined stance on the aligner unit.
The untreated wafer is automatically carried into a wafer (vacuum) treatment chamber from a vacuum container, and the treated wafer is automatically carried out of the wafer (vacuum) treatment chamber to the vacuum container.
The main cassette device (vacuum cassette) which has untreated or treated wafers is stored in a sealed box for continuous transfer into the wafer treatment chamber.
The feed and storage cassette device is stored in a sealed box for continuous transfer into a clean room.
The aligner unit can be advanced into a holding part of the main cassette device, and the main cassette device or the aligner unit is vertically moved to receive or to transfer the wafer from the aligner unit.
The robot arm device is horizontally movable between a plurality of the wafer feed cassettes.
According to another aspect of the present invention, a wafer carrying system comprises a wafer carrying device to collectively deliver a plurality of wafers between a plurality of wafer holding shelves in a vacuum cassette device provided in a treatment device in a vacuum chamber, including a wafer-loading shuttle device and a wafer-unloading shuttle device disposed at the side of the vacuum cassette device.
The shuttle devices include shuttle cassettes having a plurality of wafer support holders corresponding to a plurality of the wafer holding shelves of the vacuum cassette device.
In this event, the shuttle cassette is movable between a delivery position to deliver the wafers to/from the cassette device and a waiting position distant therefrom.
Each of the plurality of wafer holds shelves holding the wafer in each center area. The plurality of wafer support holders supports each wafer at positions on both sides in the diameter direction and away from the center area.
Under this circumstance, an aligner unit is disposed in a carrying path to the shuttle device. Further, the wafer held by a robot arm device is transferred to the aligner unit in the shuttle device, which is the intermediate cassette device. In this condition, the wafers are aligned, and directly delivered from the aligner unit to the wafer support holders of the shuttle device, which is the intermediate cassette device.
According to still another aspect of the present invention, a wafer carrying method for a wafer carrying system includes an intermediate cassette device having a plurality of wafer support holders, a robot arm device to carry a wafer, an aligner unit to align the wafer, and a wafer feed and storage cassette, and delivering the wafer to the wafer support holder after the wafer is aligned, the method comprising the steps of: taking out the wafer from the feed and storage cassette by the robot arm device to the intermediate cassette device; transferring the held wafer to the wafer support device of the intermediate cassette device; transferring the wafer to the aligner unit and aligning the wafer; and directly delivering the aligned wafer to the wafer support holderr of the intermediate cassette device in the aligner unit.
More specifically, the orientation flat (a notch) alignment of a wafer (this operation is hereinafter referred to as xe2x80x9caligningxe2x80x9d) to be transferred to a swing-type cassette referred to as a vacuum cassette (hereinafter referred to as xe2x80x9cshuttlexe2x80x9d) to collectively transfer silicon wafers is implemented in an aligner unit which can be raised/lowered in the shuttle (hereinafter referred to as xe2x80x9celevator-type (raising/lowering-type) aligner unitxe2x80x9d in a device to carry treated and untreated silicon wafers out of/into a vacuum container in a device to treat works (the silicon wafers) in a vacuum chamber such as an ion implanter.
The carrying time of the wafer to the shuttle can be improved, thereby improving the wafer treatment capacity per unit time. For example, when the wafer is carried from the wafer cassette to the shuttle, the cassette is carried in the order of: the cassettexe2x86x92(carriage by the robot arm device)xe2x86x92the aligner unitxe2x86x92the intermediate cassette; and thus the carriage by the robot can be completed in single operation.
The shuttle and the aligner unit are conventionally located separately from each other; however, space in the device can be saved by disposing them together.
In accordance with the present invention, the loading time taking several minutes (for thirteen wafers) in a conventional system is substantially halved in an example of handling thirteen 12-inch wafers.
The carriage by the robot can be completed in single operation when an elevator-type aligner unit is used in carrying wafers to the shuttle. The robot which completes the carriage of the wafer to the aligner unit can fetch the next wafer without waiting for the aligning operation, and the carrying capacity of the robot can be improved.
In addition, the wafer can be aligned at each position of the shuttle by the elevator-type aligner unit. Further, carriage of one wafer by a robot device can be completed in single operation.
Still further, the changing time of a treated wafer and an untreated wafer can be shortened, and the wafer carrying system can be saved in space.